Can't easily distinguish a child that exits with 0 from nothing having exited at all [rt.cpan.org #114447]

[toddr]

Migrated from rt.cpan.org#114447 (status was 'open')

Requestors:

• DROLSKY@cpan.org

From drolsky@cpan.org on 2016-05-17 20:36:29:

The ->result and ->full_result methods return nothing if all the children have exited 0. They also return nothing if none of the children have exited.

The only way to see if the children have actually exited is to look at ->results or ->full_results.

This is kind of annoying. It'd be nice if there was a simply way to get the status, zero or not.

From ringerc@cpan.org on 2016-11-17 05:55:10:

Strongly agree. Newer IPC::Run doesn't let you just call 'results' either, since it calls _assert_finished which will die() if still busy.

It'd be good to expose a:

->finished

or similar, with similar semantics to ->result (no index = first child, otherwise n'th child).

The docs don't mention how to tell whether a child or all children has exited at all. Even a minimal'finished' method like

sub finished {
    my IPC::Run $self = $_[0];
    return $self->{STATE} >= _finished;
}

would be helpful.

It seems like the only "official" way at the moment is to poll "pumpable" until it returns false, but this isn't really documented either. Additional text for the perldoc for 'pumpable' like:

To wait for a child process to exit during an event loop, test $h->pumpable until it returns false.

[toddr]

@autarch This seems to be a feature request. I'm not actively developing IPC::Run right now. Patches are welcome though.